Trimble modems wanted

[Badshot]

I need 3 trimble vrs modems (dcm300 I believe), installation kit too preferably but would consider them without.

 

[PJ Walker @ RTK Farming]

What do you need them for and which GPS units are they for?

 

[Badshot]

I've purchased an ethernet based RTK base, which has no radio in it. My option is either fit an external radio repeater unit and use with my existing xcn 2050, and fm750 screens on radio. Or add a modem to two 750 units and one 2050 unit. Or possibly add one modem which can be moved to whichever unit needs rtk if it's simple enough to do.

 

[PJ Walker @ RTK Farming]

Definitely the better option to go with the modems. Probably better going with the Gx450 modem though they need different cables depending on the screen. You can get them from any New Holland or Case dealer as well as Trimble. They are more expensive than dcm units but far more reliable in my experience.

 

[Badshot]

Definitely the better option to go with the modems. Probably better going with the Gx450 modem though they need different cables depending on the screen. You can get them from any New Holland or Case dealer as well as Trimble. They are more expensive than dcm units but far more reliable in my experience.

If I fitted cables to each tractor is it an easy swap of the modem unit? Or will it be a PITA? It's only really one unit at a time needs rtk but due to upgrading screens and zero resale value I have kept the old screens.

 

[PJ Walker @ RTK Farming]

Not really depends how you mount them. You probably need external aerials for the modem but you can do those with mag mounts. You will need to check settings are good everytime you move it especially if you use screens in the meantime on Egnos etc

 

[Badshot]

What settings do you mean? I have all the machine data stored, or do you mean the modem settings? Sorry for the questions, just jumped in with both feet and now learning rapidly.

 

[Wheatseeker]

I've purchased an ethernet based RTK base, which has no radio in it. My option is either fit an external radio repeater unit and use with my existing xcn 2050, and fm750 screens on radio. Or add a modem to two 750 units and one 2050 unit. Or possibly add one modem which can be moved to whichever unit needs rtk if it's simple enough to do.

Do you already have radios on the XCN and FM750s ?

 

[Badshot]

Do you already have radios on the XCN and FM750s ?

Yes I do.
But no radio on the base

 

[Wheatseeker]

Yes I do.
But no radio on the base

I’ve got an XCN 2050 with a DCM300 modem and am looking to change it for a radio if you were interested in doing something.

 

[Badshot]

I’ve got an XCN 2050 with a DCM300 modem and am looking to change it for a radio if you were interested in doing something.

I have an ag815 rtk radio fitted to the tm200 unit. I'd have to look into if it's possible to remove it and add your modem, although I have been recommended the gx450 is a better modem so realistically I'd probably go that route if I'm honest.

 

[PJ Walker @ RTK Farming]

What settings do you mean? I have all the machine data stored, or do you mean the modem settings? Sorry for the questions, just jumped in with both feet and now learning rapidly.

I mean modem and vrs settings in the screens that's all. Should be fine but always worth double checking

 

[Badshot]

I mean modem and vrs settings in the screens that's all. Should be fine but always worth double checking

Is there any difference in accuracy between a radio signal, or a modem signal?
I've been told that radio is miles better, and in particular FM1000 screens struggle on a modem (obviously I have not got one of them but am interested if it could be an issue).

 

[PJ Walker @ RTK Farming]

It totally depends on setup. If done right there should be no accuracy difference. You need to research the SIM cards you are going to use. The FM1000 screen can be a pain to get setup but once sorted should be fine. If you go from radio to modem there are so processes to go through to stop the radio being an issue. Happy to help when you get to that point.

 

[Steevo]

I have one here. Not used recently but been stored away clean and dry.

 

[Badshot]

I have one here. Not used recently but been stored away clean and dry.

300 or 450?
Cabling and antennae?

 

[Slick]

GX450 modem has been superseded by the RV55 modem now, it uses the same cables, has a different antenna although it can use the same ones as the GX450. It's the same price and it's dual sim.

 

[Badshot]

What sims are useable?

EE seems to be most used round here in GPS equipment from what I gather

 

[Badshot]

How much data is required?1gb? 5gb?

 

[Northern farmer]

Is there any difference in accuracy between a radio signal, or a modem signal?
I've been told that radio is miles better, and in particular FM1000 screens struggle on a modem (obviously I have not got one of them but am interested if it could be an issue).

This was already answered but I'd like to stress that the RTK correction data delivery means as such makes absolutely no difference in receiver accuracy. This assumes that the radio link works well, equally assumes that the cellular data link works well.

Quite obvious if you have a mountain between the base and the rover, a radio link fails. Equally obvious that the NTRIP data link fails if you do not have cellular coverage. Also obvious that the best transport option depends on local conditions.

Another possible misinterpreted fact could be the actual RTK signal provider. If it is not your own base, then the physical base is most often different when selecting between NTRIP and RTK. Distance to base is likely different. One base might support more satellite constellations than the other or the purchased correction signal may be less expensive and covers GPS only. Luckily single frequency base stations hardly exist any more.

PJ Walker covered some hardware specific issues. Good if someone is aware and in this specific Trimble scenario they may be important but "bugs aside", both transport methods should give the exact same accuracy.